Experimental Confirmation of Quantum Monodromy: The Millimeter Wave Spectrum of Cyanogen Isothiocyanate NCNCS

We have made energy-momentum maps for the experimental end-over-end rotational energy and the two-dimensional bending vibrational energy, both of which confirm the dominating effects of nontrivial quantum monodromy in cyanogen isothiocyanate. Accidental resonances in the rotational spectra yield accurate intervals between bending states

Evaluation of Intensity Information in High-resolution Gas-phase Fourier Transform Infrared Spectra* Invited Lecture

The strategies for the exploitation of intensity information in high resolution Fourier-transform infrared spectra are reviewed. Results of the evaluation of rotationally resolved and also partially resolved spectra are presented, including different types of quantitative information. The questions addressed are the equilibrium abundance of HNCNH in HpNCN, accurate intensity data for the 350 cm-1 band of N205, the transition moment of a 'forbidden ' band in HCNO, and line parameters for the bending mode v5 of NCCN

65 SCARLET AND GRAY BOOKLETS

Author Institution: Department of Physics, The Ohio State University; Columbus, Ohio 43210Video requires RealPlayer or Microsoft Silverlight to view.Delving into the archives, and drawing on the experiences of various spectroscopists, several questions will be addressed, including: What has changed since the first meeting? What has not changed since the first meeting? How did this meeting spawn not only one, but two similar meetings in Europe? How has international participation evolved over the years? How has female participation evolved? And why do we keep coming back

ASSIGNMENT OF THE MM- AND SMM-WAVE ROTATIONAL SPECTRA OF RARE ISOTOPOLOGUES OF CYANAMIDE AND THE rm(1)r_m^{(1)} MOLECULAR GEOMETRY OF NH2_2CN

G.~Moruzzi et al., {\it J.~Mol.~Spectrosc.Z.~Kisiel et al., {\it 63^{rdJ.~K.~Tyler et al., J.~Mol.~Spectrosc., {\bf 43R.~D.~Brown et al., {\it J.~Mol.~Spectrosc.J.~K.~G.~Watson et al., J.~Mol.~Spectrosc.$, {\bf 196Author Institution: Institute of Physics, Polish Academy of Sciences, Al. Lotnikow; 32/46, 02-668 Warszawa, Poland; Department of Physics, The Ohio State University, Columbus; OH 43210The cyanamide molecule is one of the prototype systems for the study of the large--amplitude inversion motion at the nitrogen atom, and it is also a potential astrophysical species. The mm-wave, smm-wave, and the far infrared spectra of the parent and the two principal deuterated isotopic species are now known in considerable detail., {\bf 190}, 353-364 (1998).}$^,~OSU~International~Symposium~on~Molecular~Spectroscopy}, WK08, 2008.} \vspace{0.2cm} Presently we report an extended analysis of rotational transitions in the $0^+$ and $0^-$ inversion states for 7 rare isotopic species of cyanamide, measured in the 118-650 GHz frequency region on a deuterated sample with natural abundance of carbon and nitrogen. The spectra of five isotopologues: H$_2$N$^{13}$CN, HDN$^{13}$CN, D$_2$N$^{13}$CN, HD$^{15}$NCN, and HDNC$^{15}$N, have been assigned for the first time. For D$_2^{15}$NCN and D$_2$NC$^{15}N the knowledge of the rotational spectrum has also been considerably improved relative to preceding work., 248-261 (1972).}^,, {\bf 114}, 257-273 (1985).} \vspace{0.2cm} The availability of spectroscopic constants for 12 different isotopic species allowed determination of the complete r_m^{(1)}$and$r_m^{(1{\rm L})} geometries, 102-119 (1999).} of cyanamide, providing direct experimental information on the pyramidal nature of the NH_2$group in cyanamide and on the nonlinearity of the NCN segment. The new experimental geometry is compared with results of$ab~initio$ calculations

High resolution fourier transform far infrared spectroscopy of CH<SUB>3</SUB>OD

The high resolution Fourier transform far infrared spectrum of the torsion rotation band of CH3OD has been recorded in the range 20-350 cm-1at a resolution of 0.002 cm-1. The spectrum shows splitting of the lines due to strong torsional, rotational, and vibrational interactions in the molecule. Assignments were possible for rotational subbands in the ground torsional state (n= 0) forKvalues up to 15 andJvalues of up to 30, for all the symmetry species. In addition, some subbands were also identified which involve torsionally excited states. A total of 63b-type subband origins, including 6Q-branch origins obtained from microwave (MW) and millimeter-wave (MMW) studies, were fitted to a semiempirical model. The molecular parameters so determined were able to reproduce the subband origins almost to within experimental uncertainty. The torsional-rotational state-dependent effective molecular parameters and the asymmetry splitting parameters have also been determined. These should prove valuable in the assignment of transitions involving torsionally excited states in the ground vibrational state

A Partial Structure of the Anti Rotamer of 1,2-Difluoroethane from the Analysis of a Band in the High-Resolution Infrared Spectrum

Two regions in the infrared spectrum of gaseous 1,2-difluoroethane at room temperature have been investigated at high resolution. Although bands due to the abundant gauche rotamer dominate the spectrum, a C-type band centered at 3001.89 cm-1 and a largely B-type band centered at 284.260 cm-1 have been shown to be due to the anti rotamer. From its rotational structure the C-type band is confirmed as being due to ν7, the antisymmetric CH2 stretching mode of au symmetry. The B-type band is due to ν18, which is largely the antisymmetric CF bending mode of bu symmetry. The rotational structure of the B-type band, recorded with exceptional resolution in a difficult spectral region, has been analyzed in detail. From the assignment of over 2000 lines, rotational constants have been fitted to the ground state and the upper state. The ground state constants are 1.057 385 7 (11), 0.129 390 34 (26), and 0.120 654 86 (19) cm-1 for this near-prolate symmetric top (κ = −0.9813). These rotational constants imply an increase of 2.5° in the CCF bond angle in going from the anti to the gauche rotamer. This adjustment is consistent with significantly larger CF bond dipole repulsion in the gauche rotamer than in the anti, despite the lower electronic energy of the gauche rotamer

Infrared Simulations Derived from Submillimeter Wave Analyses

Author Institution: Department of Physics, Wright State University, Dayton OH 45435; Department of Physics, Pittsburg State University, Pittsburg, KS 66726; Department of Physics, University of South Alabama, Mobile, AL 36688; Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warszawa, Poland; Earth Science Division, NASA Headquarters, Washington, DC 20546; Department of Physics, The Ohio State University, Columbus, OH 43210The analysis of infrared spectra of heavy molecules is challenging due to partially resolved transitions and overlapping hot bands. Quite often it is necessary to analyze jet-cooled spectra, perform a band contour analysis, or empirically measure the cross sections to provide analyses for inclusion into spectral databases for atmospheric remote sensing applications. The specificity of the pure rotational spectra in the submillimeter wave region enables the determination of the rotational manifolds of many thermally populated vibrational states. The resulting analyses provide spectral constants to directly simulate the infrared spectrum and model the Q/P/R branch transitions, account for the temperature dependence of the spectrum, and aid in the assignment and determination of band centers and transitions moments of both the fundamental and the associated hot bands. We will demonstrate the utility of this approach by discussing recent advances in the simulation of the infrared spectrum of nitric acid and chlorine nitrate

IN PURSUIT OF THE FAR-INFRARED SPECTRUM OF CYANOGEN ISO-THIOCYANATE, NCNCS, UNDER THE INFLUENCE OF THE ENERGY LEVEL DISLOCATION DUE TO QUANTUM MONODROMY

Author Institution: Department of Physics, The Ohio State University, Columbus Ohio, 43210-1106, USA; Department of Physics and Centre for Laser, Atomic, and; Molecular Sciences, University of New Brunswick, P.O. Box 4400; Fredericton NB E3B 5A3, Canada; Department of Chemistry, Adam Mickiewicz University; 60-780 Poznan, PolandQuantum Monodromy has a strong impact on the ro-vibrational energy levels of chain molecules whose bending potential energy function has the form of the bottom of a champagne bottle (i.e. with a hump or punt) around the linear configuration. NCNCS is a particularly good example of such a molecule and clearly exhibits a distinctive \mbox{mono\-dromy-induced} dislocation of the energy level pattern at the top of the potential energy hump, S.~C.~Ross~and~J.~Koput, Phys. Chem. Chem. Phys., 2010, DOI:10.1039/ B922023B}. The generalized semi-rigid bender (GSRB) wave functions are used to show that the expectation values of any physical quantity which varies with the large amplitude bending coordinate will also have mono\-dromy-induced dislocations. This includes the electric dipole moment components. High level ab initio calculations not only provided the molecular equilibrium structure of NCNCS, but also the electric dipole moment components $\mu_{\rm a}$ and $\mu_{\rm b}$ as functions of the large-amplitude bending coordinate. The calculated expectation values of these quantities indicate large ro-vibrational transition moments that will be discussed in pursuit of possible far-infrared bands. To our knowledge there is no NCNCS infrared spectrum reported in the literature